The present invention relates to a headlamp for a vehicle which is constituted to form a light distribution pattern having a cutoff line on an upper end by a so-called projector type lighting unit.
Conventionally, there has been known a headlamp for a vehicle which is constituted to irradiate a light forward from the vehicle by a projector type lighting unit.
The projector type lighting unit is constituted to collect and reflect a light emitted from a light source provided in the vicinity of an optical axis extended in the longitudinal direction of the vehicle forward from a reflector close to the optical axis and to irradiate the reflected light forward from the lighting unit through a projection lens provided in the forward part of the reflector. In the case in which a light distribution pattern having a cutoff line is to be formed on an upper end by the lighting unit, a shade is provided between the projection lens and the reflector, to shield a part of a light reflected from the reflector through the shade, thereby forming a cutoff line.
JP-A-2001-325816 discloses a headlamp for a vehicle having such a structure that a shade is moved to vertically shift the position of the cutoff line of the light distribution pattern and to tilt a lighting unit in a vertical direction, thereby displacing the whole light distribution pattern in the vertical direction corresponding to a vehicle traveling situation.
By employing the structure described in JP-A-2001-325816, it is possible to irradiate a light with a light distribution pattern at an irradiation angle corresponding to a vehicle traveling situation. Consequently, it is possible to enhance the visibility of a road surface in the forward portion of the vehicle.
However, in such a case, the shape of the lower end of a light distribution pattern is maintained to be constant. Therefore, there is a problem in that the amount of a light irradiation on the short-distance region of the road surface in the forward portion of the vehicle cannot be controlled finely.